Insulation for edgewise-wound coils.



No. 783,545. PATENTED FEB. 28. 1905. G. H. RUPLEY.

INSULATION FUR EDGEWISE WOUND SOILS.

APPLIOATION FILED JULY 21,1904.

F513}. X g n P 5 WiTNEESES: INVENTBR,

' EEUREE H.RUFLEY.

ATTY.

UNITED STATES Patented February 28, 1905.

PATENT Oriucn.

GEORGE H. RUPLEY, OF SCHENEO"ADY, NEWYORK, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

lNSULATiON FOR EDGEWlSE-WOUND COlLS- SPECIFICATION forming part of Letters Patent No. 783,546, dated February 28, 1905.

7 Application filed July 21, 1904. Serial No. 217,447.

To all mimmtjz; may ('wtcarn:

Be it known that I, Gnonon H. Burner, a citizen of the United States, residing Schenectady, in the county of Schenectady and State of New York, have invented certain new and useful Improvements in Insulation for Edgewise-Vlound Coils, of which the following is a specification.

The use of electric conductors in the form 10 of ribbons or strips has been found very advantageous in forming cdgewise windings for various types of electrical apparatus. Such windings have been employed in forming magnet-coils, resistance-coils, transformer-wind- :5 ings. and the like. Herctofore considerable difiiculty has been experienced in insuiating the adjacent turns of windings of this sort where paper, fiber, muslin, or like material is used to insulate. The usual practice has been to insert the insulating fabric between the convolutions by hand, which is slow and expensive. I cheapen the process by using a folded strip which may be accurately and quickly placed in acontinuous length and pre- 2 5 pare the strip in such a way thata weak structural fabric, such as paper, may be used.

In carrying out my invention I take the strip of paper or other insulating material and weaken its edges, so that their lengths may be readily varied. This is preferably done by providing the strips with transverse cuts which extend from the opposite edges of the paper toward the center. I then fold the paperlcngth wise, preferably alongitscenter,and

then draw the same between the convolutions of the winding after having placed the wind ing upon a closely-fitting mandrel with its convolutions drawn apart. The fold of the insulating-strip is drawn down against the sur- 4 face of the mandrel, leaving the edges extending outward between the convolutions of the winding. Where the tensile strength of the insulating material is insuflicicnt to withstand the strain of drawing it into place, I locate a thread in the fold of the strip, so as to take Up *the strain. This thread may be permanenth lcemented to the strip or not. When the strip drawn into position, the transverse cuts in the strip widen out into notches, and by reason of the staggered arrangement of the cuts 5 the open spaces in one layer come between the open spaces in the other, so that there is al' ways a layer of the insulating material between the convolutions of the conductor.

It will be apparent that my invention is capable of varied application in insulating-conductors and that the insulating-strip may be bent in its own plane without buckling or tearing to conform to any curvatn re. whether concave or convex and whether regular or broken. to

For a better understanding of the invention reference should be had to the following dcscriptiomtaken in connection with the accompanying drawings, in which I have disclosed the invention in connection with a resistance unit.

Referring tothe drawings, Figure 1 is a plan view of an insulating-strip with the pullthread in position. Fig. 2 is a similar view showing the strip after it has been cut. Fig. 3 is a. perspective view'of the cut strip after it has been folded. Fig. 4 is a view illustrating the location of the parts of the strip after it has been wound about acurvcd suface. Fig.

5 is a fragmentary view illustrating the convoiutions of a helical winding drawn apart to show the insulatingstrip in position, and Fig.

6 is an elevation of a resistance unit insulated in accordance with my invention..

Referring in detail to the drawings, 10 designetes the strip of insulating material, which may he paper, boolwnuslin, paper treated with mice, or any other suitable material. W here the tensile strength of the material employed is small, the strip may be reinforced by the 5 employment of a. thread 11, which may be permanently cemented to the strip, if desired. Before or after the thread is applied the strip is cut transversely from its opposite edges, as indicated at points 12 13. These cuts are stago gored and extend practicall to the center of the strip. The strip is then folded lengthwise, preferably along a center line, so as to leave the thread 11 in the fold wherever a thread is employed. It is of course obvious that where the thread is to be permanently attached to the strip it may be attached at any time prior to folding the strip. On the other hand, if the thread is not to be permanently attached to the strip it may be more readily slipped into place after the strip has been folded. The purpose of providing the transverse cuts 12 and 13 is to enable the edges of the strip to be lengthened, thus permitting the strip to conform to the curvature of the winding with which it is to be employed without buckling or tearing. If, for example, the winding is helical, as the winding 15 in Figs. 5 and 6, the portions of the strip adjacent to the transverse cuts 12 and 13 would bedrawn apart to form the V-shaped notches 16. (Shown in Fig. 4.) This figure also makes it clear that the staggered arrangement of the cuts 12 and 13 always insures at least one thickness of the insulating material between the convolutions, since the open spaces formed by the separation of the adjacent portions of the strip in one layer do not register with the corresponding openings in the other layer. Instead of transverse cuts 12 and 13 it is obvious that the edges of the strip -l0 may be otherwise weakened, so as to permit the edges to vary in length as the curvature of the conductors may require. After the strip has reached the form illustrated in Fig. 3 the Winding is placed upon a suitable mandrel, and with the convolutions separated the insulating-strip is drawn down between the convolutions until the fold of the strip is brought into close contact with the mandrel. This leaves the outer edges of the strip extending outvard, with the cuts 12 and 13 expanded according to the degree of curvature. hen the insulating-strip is thus positioned, the convolutions'are pressed together, and. the winding after being treated with a coating of insulating compound or otherwise, as desired, is put in place. In the way just described the insulating fabric may be applied very quickly and will always bear a definite position relatively to the conductor. Where the winding is employed in making upa resistance unit, such as that illustrated in Fig. 6, the convolutions of both the cond uctors 15 and the interposed insulating-strip are forced together and held in place by end plates 17 and 18, drawn together by a bolt 19 and nut 20. In this particular instance the end plates are provided with openings 21 to provide ventilation for the interior of the coil.

The resistance unit herein shown is simply one instance of an application of my invention. 1 have found the same particularly applicable to the insulation of transformer-windings, and it obviously may be employed in many other relations. It is also obvious that my invention may be employed in connection with many forms of conductors and under circumstances of very ditl'erent curvatures than those illustrated. I therefore do not wish to be limited to the particular use or matter herein disclosed, but aim to cover by the terms of the appended claims all uses and equivalents whiph fall within the spirit and scope of my invention.

What 1 claim as new, and desire to secure by Letters Patent of the United States. is

1. The combination of a helical conductor and astrip ofinsulating material folded lengthwise and interposed between the turns of the conductor. 7

2. The combination of a helical conductor and astrip of insulating material folded lengthwise and interposed between the turns of the conductor, with its fold adjacent the inner edge of the helix.

3. The combination of a helical conductor and astrip of insulating material folded lengthwise and interposed between the turns of the conductor and having its edges weakened.

4. The combination of a helical conductor and astrip of insulatingmaterial folded lengthwise and interposed between the turns of the conductor with its fold adjacent the inner edge of the helix and its outer edge weakened so as to lengthen when the strip is drawn into the helical form.

5. The combination of a helical conductor and a strip of insulating material provided with a central lengthwise fold, and staggered transverse cuts extending from its edges toward said fold, said strip being interposed between the turns of the conductor with its out portions displaced, thereby permitting the strip to conform to the helical formation of the conductor without buckling or tearing.

6. The combination of a helical conductor and a strip of insulating material provided with a central lengthwise fold and staggered transverse cuts extending from its edges toward said fold, said strip being interposed between the turns of the conductor with its fold adjacent the inner edge of the helix and its outer cut portions drawn apart, thereby permitting the strip to conform to the helical formation of the conductor without buckling or tearing.

7. The combination of a helical conductor and a strip of insulating material provided with a central lengthwise fold and staggered transverse cuts extending from its edge toward said fold, a thread located in the fold for drawing the strip into position, said strip being drawn thereby between the turns of the conductor with its out portions displaced. there by permitting the strip to conform to the helical formation of the conductor without buckling or tearing.

8. The combination of a helical conductor and a strip of insulating material provided with a central lengthwise fold and staggered transverse cuts extending from its edges toward said fold, a thread located in the fold for drawing the strip into position, said strip lJ(}-,' ing drawn thereby between the turns of the cond uctor with its fold adjacent the inner edges of the turns and its outer cut portions draw apa rt, thereby permitting the strip to conform to the helical formation of the conductor without buckling or tearing.

9. An insulating-strip having a thread secured thereto throughout its length, and its edge, non-adjacent the thread weakened so that it may he readily varied in length.

10. An insulatingstriphaving a thread secured thereto throughout its length and transverse cuts extending from the edge of said strip toward said thread.

11. An insulating-strip having athread secured thereto throughout its length, and staggered transverse cuts extending from its edges toward said thread.

12. An insulating-strip with a lengthwise fold and its portions non-adjacent to said fold weakened so that the strip may be bent in its own plane without tearing or buckling.

13. A resistance unit, consisting of a heiical conductor havingits turns continuousiy forced together to form a rigid tube. and insulation between the turns of the conductor consisting of a helix of insulating material folded iengthwise and having its edges non-ad jacent the fold weakened so as to vary in length according to y the curvature of the conductor.

ing their edges weakened so as to permit them when drawn into place to be curved in their own plane to conform to the curvature of the conductors, the weakened portions of one layer overlying the non-weakened portions of the other. 7

17. The combination with adjacent conductors having substantiaily parallel adjacent faces and a curvature in the direction of said faces, of an interposed strip of insulating material folded lengthwise and curved in its own plane to conform to the curvature of the condoctors.

18. The combination with the adjacent conductors having substantially parallel adjacent faces and a curvature in the direction of said faces, of an interposed strip of paper folded lengthwise and curved in its own plane to conform to the curvature of the conductor.

In witness whereof I have hereunto set my hand this 19th day of July, 1904.

GEORGE H. RUPLEY.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD. 

